Manufacture of diolefins, (isoprene,) caoutchouc, and caoutchouc-like substances.



and 500 UNITED STATES I PATENT onron.

HERMANN STERN, OF MUNICH, GERMANY.

MANUFACTURE OF IDIOLEFIN S, (ISOPRENE,) CAOUTCHOUC, AND CAOUTCHOUC-LIKE SUBSTANCES.

Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it known that I, HERMANN STERN, citizen of Bavaria, residing at Munich, Bavaria, Germany, have invented certain new and useful Improvements in the Manufacture of Diolefins, (Isoprene,) Caoutchouc, and (Jaoutchouc-like Substances; and I- do hereby declare the following to be av full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to processes of making new caoutchouc-like products by the reaction of fuming sulfuric acid on a ketone, either simple or compound, or a mixture of ketones, and the separation of the solid caoutchouc-like material from the other products of the reaction.

In place of reacting on a ketone, or a mixture ofketones, by means of sulfuric acid, the latter may also be used to react on a ketone or aliphatic oxid. The following is an example of the reaction just mentioned If, for instance, 3.5 liters of fuming sulfuric acid are added to a mixture consisting of 2 liters of acetone and 1.5 liters of ethylalcohol or 1.25 liters of ethylether, accompanied by cooling, and the liquid by-products (which can also be used for obtainin caoutchouc) are distilled off after the reaction, the acid product being neutralized approximately 2 kilos of raw caoutchouc grams of isoprene are obtained. The caoutchouc can be purified by'precipitation with alcohol or by other means.

Another method of carrying the invention into effect consists in passing unsaturated hydrocarbons, especially ethylene,

through a heated mixture of "ketones and fuming sulfuric acid containing anhydrid, especially through a mixture of acetone and fuming sulfuric acid containing anhydrid, whereby isoprene and caoutchouc are ob tained.

Ewample.

To 6 kilograms of actone contained in a vessel with a cooler thereon, I add gradually, in small portions, 9 kg. of fuming sulfuric acid containing 18 to 20% of anhydrid, in such manner that the temperature does not rise above 80 or 90 C. In about one hour and a quarterall the sul- Application filed July 17, 1914. Serial No. 851,486.

a mixture of ketones and anfuric acid will have upon the mixture,

which is still hot, is placed in another vessel provided with a gas induction pipe and an eduction pipe. Then about 3 kilograms of ethylene gas are passed through the mixture and the same is heated to a temperature of 100 to 110. In 2 or 3 hours the reaction is complete, and solid caoutchouc-like substances and liquid prod.- nets are formed. The liquids are distilled off and collected in a container cooled by a cooling mixture. The non-condensable gases escape by way of a pipe connected to this container. After neutralization of the acid mixture about 5 kilograms of raw caoutchouc and about 1.5 kilograms of isoprene with other volatile products are obtained.

The reaction involved may be represented by the following equations:

Equation 1.

CH .C0.CH3 CHaCHaOH 2H2O CHz E guatz'oml 1 is doubled so as to become converted into caoutchouc having the formula C I-I In place of ethylene I may use homologuespropylene, butylene, amylene, etc.

Instead of olefins, diolefins may be used such as allene or erythrene. Also the acetylenes may \be used such as acetylene, or methyl acetylene, and the olefin acetylenes such as diacetylene.

The raw isoprene obtained simultaneously with the caoutchouc-like body has a boiling point of 30 to, 40 C. and its composition is represented by C H By subjecting'it to the action of fuming sulfuric acid it can be polymerized to a caoutchouc substance, which is characterized by insolubility in alcohol. The polymerized body thus obtained may be identified by its composition, which corresponds to the formula C I-I as well as by its appearance and elasticity, its solubility in. the usual caoutchouc solvents, and by its insolubility in alcohol.

such as Patented Mar. 6, 1917.

been added. There- 7 By theactio'n of of vulcanization is formed which is insolu- I sulfur dichlorid a product ble in benzol, and in alcohol.

350 grams of sulfuric acid conof sulfuric anhydrid, one obtains after distilling off the; liquid products, and neutralizing with lye, .approxi'. mately 350 grams of solid caoutchouc-like substances.

Similar caoutchouc are obtained by heating acetone with 'diethyl 7 tone, or acetone with diethyl+ketone and ketone and acid or by heating methyl-ethylketone alone with acid,. or by heatingmethyl-ethylketone with propyl-butyl-ke methhyl-ethyl-ketone and propyl-butyl-ketone. V

Aromatic ketones, when heated with produces a caoutchouc-like substance, and caoutchouc-like substances are also -pro-' duced by treating acetophenone with aceand fuming sulfuric acid.

The ketones and ing out this inventionare liquid at ordinary tempera those which are ures.

VWhat I claim as myinvention and desire" Q mixed ketone is heated fuming sulfuric acid, 500 grains of acetoneare heated for about five to twenty minutes' toa temperature of from 130 to 140 degrees 6., Y 'with about taining 18 to 20% which consists in acidto a ketone and an alcohol both capaand separating substances 1 which consists in adding acid to a mixture of an aliphatic'ketone such as acetophenone,

' and. an alcohol both fuming sulfuric "acid,

In testimony whereof I hereunto tone or with one or more aliphatic ketones-ff'signature in the presence of two witnesses.

alcohols used in carry;

Q to secure by Letters Patent of the United States is r 1 In the art of producing a diolefin an a caoutchouc-like body, the improvement which consists in adding fuming sulfuric acid to a ketone capable of V ielding isopr'ene and caoutchouc and separating the roducts formed. I

1 2'; In the art of producing a diolefin and a caoutchouc-like body, the improvement adding fuming sulfuric ble. of yielding isoprene and caoutchouc,

the products formed.

3. In the art of producing a diolefinand acaoutchouc-like body, the improvement which consists in adding fuming sulfuric acid to an aliphatic ketone and an alcohol both capable of yielding isoprene and caoutchouc and separating the products formed. p w

4,. In the art of producing a diolefin and a caoutchouc-like body, the improvement fuming sulfuric capable of yielding isoprene and caoutchouc and products formed.

aflix my HERMANN STERN.

separating the 

